Ok, solving proportions using cross products...5/n+3 = 7/4...are they asking for x or the whole proportion?

Question

I'm trying to figure this out (Geometry, by the way) and don't really know what they're asking for. It says "Solve each proportion by using cross products." and the problem is 5/n+3 = 7/4 (5 over n+3 is equal to 7 over 4)...answers anybody??

Answer 1

5/n+3 = 7/4
7(n + 3) = 5.4
7n + 21 = 20
7n = 20 - 21
7n = -1
n = -1/7
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Answer 2

5/(n+3)=7/4 cross multiply
20=7*(n+3)
20=7n+21
-1=7n
n=-1/7
They just want the value n that makes the proportion true.